There is a much faster way of flashing if you have already flashed xbr_1:
The difference between xbr_1 and xbr_3 is only in in the beginning of the file. So you can update your 256/512 MB Jasper much quicker. Here's the way that worked for me:
1. Extract the first 90 blocks of the xbr_3 file
NandPro.exe XBR_JasperBB_8955_3: -r512 xbr.bin 0 90
2. Insert your keyvault into the generated file
NandPro.exe xbr.bin: -w512 rawkv.bin 1 1
3. Flash the file to your NAND with lpt or usb
NandPro.exe lpt: -w512 xbr.bin
4. Finished in roundabout 5 min
Testing done by me:
1. Starting XeLL with the Eject-button -> working
2. Booting Gentoo -> working
3. Booting hacked NXE -> working
4. Playing TrialsHD -> working (about half an hour without any slowdowns or freezes)
5. Playing Assassins Creed 2 from external USB-HDD (default.xex not patched) -> working (about 2 hours without slowdowns or freezes)
Comment:
-Of course I am not responsible for any damage that may be done to your console. I don't know/tried it with a NAND with bad blocks at the beginning because I only have one 512MB Jasper. I don't know if it works with 256 MB Japsers. I'm just describing the way that worked for me.
The idea of finding the differences in the two XBR Versions is not my work, it was done by the TheCounter(Gulli).